IssueTracker

Thank you for the nice reproduction. The problem is in the library that defines a service loader implementation file incorrectly. The file META-INF/services/org.xmlpull.v1.XmlPullParserFactory contains:

org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer

The spec clearly states that it should be one per line: https://docs.oracle.com/javase/6/docs/api/java/util/ServiceLoader.html

A service provider is identified by placing a provider-configuration file in the resource directory META-INF/services. The file's name is the fully-qualified binary name of the service's type. The file contains a list of fully-qualified binary names of concrete provider classes, one per line...

R8 also gives a warning regarding that:

Warning in /usr/local/google/home/mkroghj/dumps/b279996549/dump/program.jar:META-INF/services/org.xmlpull.v1.XmlPullParserFactory:
Unexpected reference to missing service implementation class in META-INF/services/org.xmlpull.v1.XmlPullParserFactory: org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer.

The reason the context is FastServiceLoader.load is because that is where we enqueue the potential services that can be loaded. I guess this could try and figure out the concrete types that could be loaded instead of all types, but that is difficult since the method takes a class as argument.

R8 will read the type in the implementation as a type with name org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer. You therefore, in principle, need to write -dontwarn org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer. Now the problem here is that -dontwarn takes a list of classes as argument, so we parse that into something similar to:

-dontwarn org.kxml2.io.KXmlParser
-dontwarn org.kxml2.io.KXmlSerializer

The only thing you can write is a prefix, so you could do -dontwarn org.kxml2.io.KXml* and that will silence the compiler and succeed.

Regarding the library, I checked if the error was still present, but the service file was corrected over 3 years ago: https://github.com/kobjects/kxml2/commit/de05dd4abfcec52ff564f0cdb01bd86d67dc5ceb

You could see if an update of the library you are using is available or use the -dontwarn pattern above. Will be marking this as WAI.

I have tried above pattern but that also fail

-dontwarn org.kxml2.io.KXml*

Can you please confirm from sample file with corrected pattern and working solution ?

It should be two **. You can decide on any prefix you desire as long as it matches the path.

-dontwarn org.kxml2.io.KXml**

Thanks mk@, using that pattern issue resolved for now.

jordi.ortuno@innocv.com, I think you problem might be different. It looks like you have classes from the org.xmlpull.v1 in your input. Classes in that namespace are also in the Android runtime, https://developer.android.com/reference/org/xmlpull/v1/package-summary.

i have a slightly different warning message

Missing class org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer (referenced from: java.util.List androidx.test.internal.platform.ServiceLoaderWrapper.loadService(java.lang.Class))

Tried all patterns provided wiithout success:

-dontwarn org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer

-dontwarn org.kxml2.io.KXmlParser
-dontwarn org.kxml2.io.KXmlSerializer

-dontwarn org.kxml2.io.KXml*

-dontwarn org.kxml2.io.KXml**

it turns out in my case (AGP 8.0) the error was referring releaseAndroidTest which needs its own testProguardFiles, as described in this issue